Stochastic labour market shocks, labour market programmes, and human capital formation: a theoretical and empirical analysis

This paper develops a life-cycle model of labour supply that captures endogenous human capital formation allowing for individual’s heterogeneous responses to stochastic labour market shocks. The shocks determines conditions in the labour market and sort individuals into three labour market regimes; employment, unemployment with and unemployment without participation in labour market programmes. The structural model entails time independent stochastic shocks that have transitory effects on monetary returns while the effect on human capital formation may be permanent. The permanent effect may justify the existence of active labour market programmes if these programmes imply non-depreciating human capital and human capital depreciation is detected for the non-participant unemployed. Using several years of the Swiss Labour Force Survey (SAKE, 1991 – 2004) the empirical section compares the dynamic formation of human capital between labour market regimes. The results are consistent with the assumptions of the structural model and suggest human capital depreciation for unemployment without programme participation. They further show that labour programmes may act as a buffer to reduce human capital loss while unemployed.Human capital formation, life-cycle labour supply models, active labour market policies, search activities, productivity shocks, unemployment

Stochastic labour market shocks, labour market programmes, and human capital formation: a theoretical and empirical analysis

This paper develops a life-cycle model of labour supply that captures endogenous human capital formation allowing for individual’s heterogeneous responses to stochastic labour market shocks. The shocks determines conditions in the labour market and sort individuals into three labour market regimes; employment, unemployment with and unemployment without participation in labour market programmes. The structural model entails time independent stochastic shocks that have transitory effects on monetary returns while the effect on human capital formation may be permanent. The permanent effect may justify the existence of active labour market programmes if these programmes imply non-depreciating human capital and human capital depreciation is detected for the non-participant unemployed. Using several years of the Swiss Labour Force Survey (SAKE, 1991 – 2004) the empirical section compares the dynamic formation of human capital between labour market regimes. The results are consistent with the assumptions of the structural model and suggest human capital depreciation for unemployment without programme participation. They further show that labour programmes may act as a buffer to reduce human capital loss while unemployed.Human capital formation, life-cycle labour supply models, active labour market policies,search activities, productivity shocks, unemployment.

Comments on Noncommutative Field Theories

We discuss some aspects of noncommutative quantum field theories obtained from the Seiberg-Witten limit of string theories in the presence of an external B-field. General properties of these theories are studied as well as the phenomenological potential of noncommutative QED.Comment: 15 pages. Based on talks at the 9th Adriatic Meeting (Dubrovnik, Croatia) and at String Phenomenology 2003 (Durham, UK). v2 references adde

Topics in String Theory and Quantum Gravity

These are the lecture notes for the Les Houches Summer School on Quantum Gravity held in July 1992. The notes present some general critical assessment of other (non-string) approaches to quantum gravity, and a selected set of topics concerning what we have learned so far about the subject from string theory. Since these lectures are long (133 A4 pages), we include in this abstract the table of contents, which should help the user of the bulletin board in deciding whether to latex and print the full file. 1-FIELD THEORETICAL APPROACH TO QUANTUM GRAVITY: Linearized gravity; Supergravity; Kaluza-Klein theories; Quantum field theory and classical gravity; Euclidean approach to Quantum Gravity; Canonical quantization of gravity; Gravitational Instantons. 2-CONSISTENCY CONDITIONS: ANOMALIES: Generalities about anomalies; Spinors in 2n dimensions; When can we expect to find anomalies?; The Atiyah-Singer Index Theorem and the computation of anomalies; Examples: Green-Schwarz cancellation mechanism and Witten's SU(2) global anomaly. 3-STRING THEORY I. BOSONIC STRING: Bosonic string; Conformal Field Theory; Quantization of the bosonic string; Interaction in string theory and the characterization of the moduli space; Bosonic strings with background fields. Stringy corrections to Einstein equations; Toroidal compactifications. $R$-duality; Operator formalism 4-STRING THEORY II. FERMIONIC STRINGS: Fermionic String; Heterotic String; Strings at finite temperature; Is string theory finite? 5-OTHER DEVELOPMENTS AND CONCLUSIONS: String ``Phenomenology''; Black Holes and Related SubjectsComment: 133 pages, 22 figures (not included, available upon request), LaTe

Bounds on Quantiles in the Presence of Full and Partial Item Nonresponse

Microeconomic surveys are usually subject to the problem of item nonresponse, typically associated with variables like income and wealth, where confidentiality and/or lack of accurate information can affect the response behavior of the individual. Follow up categorical questions can reduce item nonresponse and provide additional partial information on the missing value, hence improving the quality of the data. In this paper we allow item nonresponse to be non-random and extend Manski’s approach of estimating bounds to identify an upper and lower limit for the parameter of interest (the distribution function or its quantiles). Our extension consists of deriving bounding intervals taking into account all three types of response behavior: full response, partial (categorical) response and full nonresponse. We illustrate the theory by estimating bounds for the quantiles of the distribution of amounts held in savings accounts. We consider worst case bounds which cannot be improved upon without additional assumptions, as well as bounds that follow from different assumptions of monotonicity.item nonresponse;bracket response;bounds and identification

Nonparametric Bounds in the Presence of Item Nonresponse, Unfolding Brackets and Anchoring

Household surveys often suffer from nonresponse on variables such as income, savings or wealth.Recent work by Manski shows how bounds on conditional quantiles of the variable of interest can be derived, allowing for any type of nonrandom item nonresponse.The width between these bounds can be reduced using follow up questions in the form of unfolding brackets for initial item nonrespondents.Recent evidence, however, suggests that such a design is vulnerable to anchoring effects.In this paper Manski's bounds are extended to incorporate the information provided by the bracket respondents allowing for different forms of anchoring.The new bounds are applied to earnings in the 1996 wave of the Health and Retirement Survey.The results show that the categorical questions can be useful to increase precision of the bounds, even if anchoring is allowed for.microeconomics;nonresponse

Nonparametric Modeling of the Anchoring Effect in an Unfolding Bracket Design

Household surveys are often plagued by item non-response on economic variables of interest like income, savings or the amount of wealth. Manski (1989,1994, 1995) shows how, in the presence of such non-response, bounds on conditional quantiles of the variable of interest can be derived, allowing for any type of non-random response behavior. Including follow up categorical questions in the form of unfolding brackets for initial item non-respondents, is an effective way to reduce complete item non-response. Recent evidence, however, suggests that such design is vulnerable to a psychometric bias known as the anchoring effect. In this paper, we extend the approach by Manski to take account of the information provided by the bracket respondents. We derive bounds which do and do not allow for the anchoring effect. These bounds are applied to earnings in the 1996 wave of the Health and Retirement Survey (HRS). The results show that the categorical questions can be useful to increase precision of the bounds, even if anchoring is allowed for.unfolding bracket design;anchoring effect;item nonresponse;bounding intervals;nonparametrics

Nonparametric Bounds on the Income Distribution in the Presence of Item Nonresponse

Item nonresponse in micro surveys can lead to biased estimates of the parameters of interest if such nonresponse is nonrandom. Selection models can be used to correct for this, but parametric and semiparametric selection models require additional assumptions. Manski has recently developed a new approach, showing that, without additional assumptions, the parameters of interest are identified up to some bounding interval. In this paper, we apply Manski’s approach to estimate the distribution function and quantiles of personal income, conditional on given covariates, taking account of item nonresponse on income. Nonparametric techniques are used to estimate the bounding intervals. We consider worst case bounds, as well as bounds which are valid under nonparametric assumptions on monotonicity or under exclusion restrictions.nonparametrics;bounds and identification;sample non-response